InSb-based photodiode detectors are used in many infrared sensor applications. InSb-based detectors have found particular use in infrared detection and imaging applications in the 3-5 micron IR wavelength band. Infrared detectors and imaging devices such as FLIRs (Forward-Looking Infrared) are particularly useful due to their ability to operate in conditions where imaging operations in the visible spectrum are being negatively impacted by reduced visibility. For example, infrared imaging devices can provide useful real-time images at night. Infrared imaging devices also can provide useful real-time images during daytime when imaging operations in the visible spectrum have been degraded due to smoke or sand.
Those designing InSb-based photodiodes and sensor arrays are always seeking ways to improve the sensitivity of such devices. Increased sensitivity generally makes detectors and imaging devices more useful because the noise-equivalent power is reduced, meaning that less thermal contrast between targets and background is required in order to distinguish the targets from the background.
Limitations in sensor performance often are the by-product of manufacturing processes. In particular, manufacturing processes create minute imperfections in detector surfaces. These imperfections reduce the noise performance of sensors from ideal. Accordingly, those skilled in the art are always seeking manufacturing processes that result in relatively fewer imperfections and thus increase the noise performance of such sensors.